1. Field of the Invention
The present invention relates to a server computer that is connected to the Internet, particularly to a server computer that functions as an electronic bulletin board and a mail server.
2. Related Art
Computers that are connected to the Internet contain user computers used by many unspecified users and server computers that provide various services to the user computers.
One of the server computers has an electronic bulletin board system and/or a mail server, which are for mediating information between the user computers. The electronic bulletin board system makes a message, which is contributed from a person who wants to post the message via the Internet, into a definite screen data, generally in a HTML format, and opens the screen data to public on the Internet.
The mail server receives an e-mail that a sender sent on the Internet according to a generally known SMTP procedure, and sends this e-mail to a mail address of a recipient of the e-mail. Then, the mail server sends the e-mail in an e-mail storage location, a mail box that corresponds to the mail address of the recipient to the user computer of a recipient who accessed to the mail server according to a POP procedure.
On the other hand, a hyperlink is known as a main system in the Internet. The hyperlink, hereinafter referred to as a link, links a text file, image data and voice data in sentences. A document created by using the link is a hypertext.
For example, when a hypertext document is being read on a user computer, a user performs a proper instruction operation, typically a click operation of a mouse for a character or a picture for which a link is set in the document. The instructed character or picture is linked with URL (Uniform Resource Locator), and the user computer obtains a specified document in a specified location on the Internet or activates a program in a specified location according to the URL. Of course, this link can be set in a text that includes a main message text and a main e-mail text posted on the electronic bulletin board.
When a document of the message or the e-mail is transformed into the hypertext, a creator of the document selects a text portion which the creator wishes to set the link, and performs operation of linking the text portion with a URL as a link destination. However, the hyperlink never be set unless the document creator intends to. Therefore, when a document reader wants to deepen understanding of the text included in the document, or to obtain related information, the reader has no option but to search such information by using a search engine that is open to public on the Internet and so on.
Moreover, even if the link is set, there is a case where a Web page of the link destination is already closed or the URL is changed. In order to cope with such cases, the document creator must check whether a setting of a link destination is effective or not as occasion demands. The link destination setting needs to be changed when a change to the link has been made.